Printing in a helical pattern on elongated cylindrical articles

ABSTRACT

A machine for printing indicia on cylindrical articles, for example plastic pipe, in a helical pattern is provided with at least one printing unit mounted on a frame rotatable about the pipe, motor driven means for rotating the frame, and motor driven means for rotating the roll of each printing unit which contacts the pipe. Preferably, there are two printing units mounted in opposition to each other. Each printing unit includes an inking system which prevents loss of ink during the rotation of the frame.

United States Patent 191 Shofner et al.

[ PRINTING IN A HEIJCAL PATTERN ON ELONGATED CYLINDRICAL ARTICLES [75] Inventors: Don L. Shofner; Leroy E. Robinson;

Robert J. Martinovich, all of Bartlesville, Okla.

[73] Assignee: Phillips Petroleum Company [22] Filed: Sept. 22, 1972 21] Appl. No.: 291,173

-[52] US. Cl 101/37, 101/350, 101/363,

118/221, 11'8/234,'l18/D1G. 21

[51] Int. Cl B4lf 17/10 [58] Field of Search....... 101/36, 37, 350, 363, 349; 118/234, 221, DIG. 21, 240

[56] 1 References Cited UNITED STATES PATENTS 2,344,610 3/1944 Hargreaves et a1... 101/36 2,537,884 l/1951 Forsberg 101/36 X 2,351,224

6/1944 Nystrom l01/36X Feb. 5, 1974 3,585,932 6/1971 Granger 101/350 2,863,386 12/1958 .Burtchaell... ....l0l/212 2,986,088 5/1961 Chase et al. 1121/426 X 1,900,266 3/1933 Wood 101/363 Primary Examiner-Robert E. Pulfrey Assistant Examiner-Clifford D. Crowder Attorney, Agent, or Firm-Quigg and Oberlin 57 ABSTRACT A machine for printing indicia on cylindrical articles,

for example plastic pipe, in a helical pattern is provided withat least one printing unit mounted on a frame rotatable about the pipe, motor driven means for rotating the frame, and motor driven means for rotating the roll of each printing unit which contacts the pipe. Preferably, there are two printing units mounted in opposition to each other. Each printing unit includes an inking system which prevents loss of ink during the rotation of the frame.

9 Claims, 6 Drawing Figures PATENIEUFEB 5:974 v 3,789.754

saw 2 or 5 FIG. 3

PATENTED FEB 9 4 SHEET 3 0F 5 FIG. 4

PAIENTED FEB 5W 3,789 754 saw u or 5 FIG. 5

Pmmmrm 5 91 3,789,754

snmsois FIG. 6

PRINTING IN A HELICAL PATTERN ON ELONGATED CYLINDRICAL ARTICLES This invention relates to apparatus for printing indicia on a cylindrical article in a helical pattern.

ln previous machine s-for printing cylindrical articles in a spiral or helical pattern, it has been common to utilize the longitudinal motion of the cylindrical article .to frictionally drive the printing rolls. Such machines present significant problems with respect to printing on cylindrical articles of thermoplastic material having a smooth exterior surface. Thermoplastic material, such as the polyolefins, poly(vinyl chloride) and the ABS resinsemployed in the manufacture of plastic pipe, has a-very low coefficient of friction, thus making it very difficult, if not impossible, for the printing rolls to be frictionally driven by the movement of the pipe Without slippage. If the surface of the printing roll is roughened to increase the frictional coefficient, the surface of plastic pipe becomes scuffed and marred. Difficulties have also been encountered in providing a uniform supply of ink to the printing roll without loss of ink due to the rotation of the printing unit about the pipe.

ln accordance with the present invention, these disadvantages of prior art systems can be avoided by employing motor driven means'for rotating the printing roll which contacts the article to be printed and by utilizing an inking roll and ink reservoir system provided with means for preventing loss of ink.

Accordingly, it is anobject of the invention to provide' a new and improved apparatus for printing indicia on cylindrical articles in a helical pattern. Another object of the invention is to print indicia on a cylindricalarticle in a helical pattern without smearing the indicia and without marring the surface of the article. A further objectof the invention is to preventloss of ink from a rotating printing unit. Other objects, aspects and advantages of the invention will be apparentfrom a study of the specification, the drawings and the appended claims to the invention.

In the drawings,

. FIG. 1 is a front elevational view', wi th a portion of one member broken away for-clarity, of a pipe printer in accordance with the present invention; I

FlG. 2 isa slide elevational view taken along line 22 of FIG. 1; v

gitudinal axis by means of motor 29 driving chain 31 and gear28.

Outlet plate 18 has a circular opening32. A cylindrical sleeve 33 is positioned coaxially with sleeve 23 and opening 32 by rollers 34, 35 and 36 riding in groove 37 in sleeve 33. Rollers 34, 35 and 36 are rotatably mounted on shafts secured to outlet plate 18. One end of each of tubular bars 38 and 39 is secured to plate 42 while the other end of each of bars 38 and 39 is secured to plate 43. Plate 42 is bolted to bracket 44 which in turn is welded to sleeve 23. Plate 43 is bolted to bracket 45 which in turn is welded to sleeve 33. Similarly, tubular bars 40 and 41 are secured to plates 46 and 47, which in turn are-bolted to brackets 48 and 49, the latter elements being welded to sleeves 23 and 33. Thus sleeves 23 and 33 and bars 38, 39, 40 and 41 rotate as an integral unit about the common axis of sleeves 23 and 33. The pipe 50 to be printed is moved longitudinally by suitablemeans, for example, by the rotation of nip rolls 60 and 70. Pipe 50 passes through-opening 21, sleeve 22, sleeve 33 and opening 32, with the longitudinal axis of pipe 50 coinciding with the longitudinal axis of sleeves 22 and 33 and openings 21 and 32.

A first printing unit 51 is adjustably mounted on bar 38 by means of bolt 52, with the cylindrical surface of transfer roll 53 being in tangential contact with the exterior surface of pipe 50. A second printing unit 51a is adjustably mounted on bar 40 by means of bolt 52a with the cylindrical surface of transfer roll 53a being in tangential contact with the exterior surface of .pipe at a point 180 from the point of contact between transfer roll 53 and pipe50, the two points of contact'being in a plane perpendicular to the longitudinal axis of pipe 50. A first spring biased ball bearing assembly 54 is adjustably mounted on bar 39 with the ball bearing-55 being in contact with the exterior surface of pipe 50. A second spring biased ball bearing assembly 54a is adjustably mounted on'bar 41 with the ball bearing 55a thereof being in contact with the exterior surface of pipe 50 at a point 180 from the point of contact of ball bearing 55 and pipe 50. Ball bearings 55 and 55a are resiliently biased toward pipe 50 by springs 56 and 56a,

, respectively.

' FIGS. 3 and 4 are partial elevational views in cross section taken along line 33 of FIG. 2;

FIG. 5 is a cross sectional view taken along line 55 of FIG. 1; and

. FIG. 6 is a partial view of an ink reservoir with the cover removed.

The base frame of the pipe printer comprises L-beam standards l1, 12, 13' and 14, base plate 15, motor mount plate 16, inlet plate 17, outlet plate 18, and legs 19 joined together by suitable means, for example by welding. lnlet plate 17 has a circular opening 21 therein,'and a cylindrical sleeve 22 having an internal diameter equal to the diameter of opening 21 is welded to plate 17 with the'opening 21 and sleeve 22 being coaxial. A cylindrical sleeve 23 having an internal diameter slightly larger than the external diameter of sleeve 22 is positioned about sleeve 22. Sleeve 23 is maintained in a coaxial relationship with sleeve 22 by rollers 24, 25 and 26 which are rotatably mounted on shafts secured to plate 17 and which ride in groove 27 in sleeve 23. Annular gear 28 is welded to the exterior surface of sleeve 23. Sleeve 23 is rotated about its lon- Printing units 51 and 51a are identical; thus, forth sake of simplicity, only unit 51 will be described in detail. Transfer roll 53 is positioned with the rotational axis of roll 53 being in a plane inclined to the longitudinal axis of pipe 50 so that the desired indicia is printed on the exterior surface of pipe 50 in a helical pattern. Transfer roll 53 is preferably formed with at least a resilient'cylindrical surface to prevent scarring of the surface of pipe 50. Transfer roll 53 and pulley 61 are both secured to drive shaft 62, while printing roll 63 and pulley 64 are securedto rotatable shaft 65. Inking roll 66 and pulley 67 are secured to rotatable shaft 68, while wiping roll 69 and pulley 71 are secured to rotatable shaft 72. An idler roll 73 is mounted on rotatable shaft 74. A belt 75 makes contact with pulleys 61, 64, 67, 71 and 73 so that the rotation of shaft 62 effects the rotation of shafts 65, 68, 72 and 74. Thus transfer roll 53, printing roll 63, inking roll 66 and wiping roll 69 are driven in synchronism. Printing roll 63 has an annular band 76 on the cylindrical periphery thereof so that the outer face of band 76 makes rolling contact with the cylindrical surfaces of inking roll 66 and transfer roll 53. The indicia to be printed in a spiral band'on pipe 50 is formed as the raised type portions of the outer face of band 76. inking roll 66 is positioned so that one portion thereof is in contact with an ink reservoir 77 in housing 78. As shown in FIG. 6, inking roll 66 rotates clockwise with the cylindrical surface thereof passing in sequence from ink reservior 77 into wiping contact with adjustable doctor blade 79 to provide a layer of ink of uniform thickness and then into contact with the indicia type band 76 on printing roll 63. After contact with band 76, the portion of the cylindrical surface of inking roll 66 carrying the unused ink passes into contact with or at least in close proximity to wiping roll 69. Roll 69 rotates in a counterclockwise manner to cooperate with roll 66 to return the unused ink to reservoir 77 and to prevent leakage of ink between rolls 66 and 69 during rotation of the printing carriage about pipe 50. An adjustable doctor blade 81 prevents roll 69 from carrying any significant amount of ink out of reservoir 77. Ink can be supplied to reservoir 77 through opening 82 from a pressurized cartridge or other suitable means. Preferably, at least one of rolls 66 and 69 has a resilient cylindrical surface to prevent binding when these rolls are placed in contact with each other. In order to effect the rotation of shafts 62 and 62a, an annular spur gear 83 is secured to the outer cylindrical surface of sleeve 22. Mating spur gear wheels 84 and 84a are rotatably secured on shafts 85 and 85a, respectively, so that the gear teeth of gear wheels 84 and 84a intermesh with the gear teeth of gear 83. Shafts 85 and 85a are mounted in brackets 86 and 86a, respectively, secured to sleeve 23 by flanges 87 and 87a. Thus the rotation of sleeve 23 relative to sleeve 22 results in the rotation of shafts 85 and 85a at a rate proportional to the rate of rotation of sleeve 23. Shaft 85 is connected through toggle action U-joint 88, shaft 89 and universal gear joint 91 to shaft 62, while shaft 85a is similarly connected through toggle action U-joint 88a, shaft 894 and universal gear joint 91a to shaft 62a. Different diameter pipes can be accomodated by the adjustment of bolts 52 and 52a and ball bearing assemblies 54 and 54a. The angle of the helically printed patterns can be adjusted by varying the longitudinal speed of pipe 50 and the angle of inclination of transfer rolls 53 and 53a to-the longitudinal axis of pipe 50. If desired, at least one of plates 45 and 49 can be formed in two parts, with one part secured to sleeve 33 and the second part being secured to the respective support bars. The two parts of the plate can be provided with biasing springs and latching means to releasably secure the two parts together. Thus, the printing units can be moved apart to facilitate the initial insertion of pipe 50 into the unit or the removal of pipe 50 from the unit. Reasonable variations and modifications are possible within the scope of the foregoing disclosure, the drawings and the appended claims to the invention.

We claim: 1. Apparatus for printing indicia in a spiral pattern on a longitudinally elongated cylindrical article which comprises a base, a support framework rotatably mounted on said base for rotation about the longitudinal axis of said article, means for effecting the rotation of said framework about said axis, a first printing unit mounted on said framework and having a first roll for tangentially contacting the exterior surface of said article with the rotational axis of said first roll being in a plane inclined to said longitudinal axis for applying a desired indicia to the exterior surface of said article in a first helical pattern as said article is moved along said longitudinal axis, and means responsive to the rotation of said framework and independent of the longitudinal movement of said article for positively rotating said first roll about its rotational axis at a rate proportional to the rate of rotation of said framework.

2. Apparatus in accordance with claim 1 wherein said means for rotating said first roll comprises an annular gear having an internal diameter larger than the external diameter of said article and fixedly mounted on said base coaxial with said article, a gear wheel rotatably mounted on said framework and having gear teeth intermeshing with the gear teeth of said annular gear so that the rotation of said framework causes the rotation of said gear wheel, and means for rotatably driving said roll responsive to the rotation of said gear wheel.

3. Apparatus in accordance with claim 1 further comprising a second printing unit mounted on said framework and having a second roll for contacting the exterior surface of said article with the rotational axis of said second roll being in a plane inclined to the longitudinal axis of said article for supplying a desired indicia to the exterior surface of said article in a second helical pattern as said article is moved along said longitudinal axis, and means responsive to the rotation of said framework and independent of the longitudinal movement of said article for positively rotating said second roll about its rotational axis at a rate proportional to the rate of rotation of said framework.

4. Apparatus in accordance with claim 3 wherein said means for rotating said'first roll and said means for rotating said second roll comprise an annular gear having an internal diameter larger than the external diameter of said article and fixedly mounted on said base coaxial with said article, first and second gear wheels rotatably mounted on said framework and having gear teeth intermeshing with the gear teeth of said annular gear so that the rotation of said framework causes the rotation of said first and second gear wheels, means for rotatably driving said first roll responsive to the rotation of said first gear wheel, and means for rotatably driving said second roll responsive to the .rotation of said second gear wheel.

5. Apparatus in accordance with claim 3 wherein said first and second rolls contact the exterior surface of said article at' locations which are in a plane at least substantially perpendicular to said longitudinal axis and spaced substantially apart with respect to said longitudinal axis.

6. Apparatus in accordance with claim 1 wherein said first printing unit further comprises an ink reservoir, a

cylindrical inking roll having a portion of the periphery thereof in contact with the ink in said reservoir, a cylindrical printing roll having raised indicia on the cylindrical surface thereof, said printing roll being positioned so that said raised indicia sequentially contacts the cylindrical surface of said inking roll and the cylindrical surface of said first roll, and means responsive to the tional axis of said inking roll and positioned in at least close proximity to the cylindrical surface of said inking roll at the point of reentry of the cylindrical surface of the inking roll into said ink reservoir, means for rotating said wiping roll counter to the rotation of said inking roll so that said wiping roll cooperates with said inking roll to return any unused ink to said ink reservoir, and a second doctor blade positioned adjacent the cylindrical surface of said wiping roll at the point of emergence of the cylindrical surface of said wiping roll from said ink reservior to prevent the removal of. any subfirst roll has a resilient cylindrical surface. 

1. Apparatus for printing indicia in a spiral pattern on a longitudinally elongated cylindrical article which comprises a base, a support framework rotatably mounted on said base for rotation about the longitudinal axis of said article, means for effecting the rotation of said framework about said axis, a first printing unit mounted on said framework and having a first roll for tangentially contacting the exterior surface of said article with the rotational axis of said first roll being in a plane inclined to saId longitudinal axis for applying a desired indicia to the exterior surface of said article in a first helical pattern as said article is moved along said longitudinal axis, and means responsive to the rotation of said framework and independent of the longitudinal movement of said article for positively rotating said first roll about its rotational axis at a rate proportional to the rate of rotation of said framework.
 2. Apparatus in accordance with claim 1 wherein said means for rotating said first roll comprises an annular gear having an internal diameter larger than the external diameter of said article and fixedly mounted on said base coaxial with said article, a gear wheel rotatably mounted on said framework and having gear teeth intermeshing with the gear teeth of said annular gear so that the rotation of said framework causes the rotation of said gear wheel, and means for rotatably driving said roll responsive to the rotation of said gear wheel.
 3. Apparatus in accordance with claim 1 further comprising a second printing unit mounted on said framework and having a second roll for contacting the exterior surface of said article with the rotational axis of said second roll being in a plane inclined to the longitudinal axis of said article for supplying a desired indicia to the exterior surface of said article in a second helical pattern as said article is moved along said longitudinal axis, and means responsive to the rotation of said framework and independent of the longitudinal movement of said article for positively rotating said second roll about its rotational axis at a rate proportional to the rate of rotation of said framework.
 4. Apparatus in accordance with claim 3 wherein said means for rotating said first roll and said means for rotating said second roll comprise an annular gear having an internal diameter larger than the external diameter of said article and fixedly mounted on said base coaxial with said article, first and second gear wheels rotatably mounted on said framework and having gear teeth intermeshing with the gear teeth of said annular gear so that the rotation of said framework causes the rotation of said first and second gear wheels, means for rotatably driving said first roll responsive to the rotation of said first gear wheel, and means for rotatably driving said second roll responsive to the rotation of said second gear wheel.
 5. Apparatus in accordance with claim 3 wherein said first and second rolls contact the exterior surface of said article at locations which are in a plane at least substantially perpendicular to said longitudinal axis and spaced substantially 180* apart with respect to said longitudinal axis.
 6. Apparatus in accordance with claim 1 wherein said first printing unit further comprises an ink reservoir, a cylindrical inking roll having a portion of the periphery thereof in contact with the ink in said reservoir, a cylindrical printing roll having raised indicia on the cylindrical surface thereof, said printing roll being positioned so that said raised indicia sequentially contacts the cylindrical surface of said inking roll and the cylindrical surface of said first roll, and means responsive to the rotation of said first roll for rotating said inking roll and said printing roll.
 7. Apparatus in accordance with claim 6 wherein said first printing unit further comprises a first doctor blade positioned adjacent the cylindrical surface of said inking roll at the point of emergence of the cylindrical surface of the inking roll from said ink reservoir, to permit said inking roll to withdraw a substantially uniform coating of ink from said ink reservoir, a cylindrical wiping roll having its rotational axis parallel to the rotational axis of said inking roll and positioned in at least close proximity to the cylindrical surface of said inking roll at the point of reentry of the cylindrical surface of the inking roll into said ink reservoir, means for rotating said wiping roll counter to the rotation of said inkinG roll so that said wiping roll cooperates with said inking roll to return any unused ink to said ink reservoir, and a second doctor blade positioned adjacent the cylindrical surface of said wiping roll at the point of emergence of the cylindrical surface of said wiping roll from said ink reservior to prevent the removal of any substantial amount of ink from said ink reservior due to the rotation of said wiping roll.
 8. Apparatus in accordance with claim 7 wherein at least one of said inking roll and said wiping roll has a resilient cylindrical surface.
 9. Apparatus in accordance with claim 1 wherein said first roll has a resilient cylindrical surface. 